Multicircuit electric safety switch



April 21, 1953 A. G. SEIFRIED 2,636,088

MULTICIRCUIT ELECTRIC SAFETY SWITCH Filed Nov. 22, 195o Patented Apr. 21, 1953 2,636,088 MULTICIRCUIT ELECTRIC SAFETY SWITCH Anton G. Seifried, Akron, Ohio, assigner to The B. F. Goodrich Company, New York, N. Y., a corporation of New York Application November 22, 1950, Serial No. 197,007

'l Claims.

The invention relates to electrical circuitbreaking switches and especially to electrical safety switches suitable for multi-circuit use and suitable for use under conditions where re is a end portions or flanges I5, I6 interconnected by a substantially flat base portion or seating portion I 4a. The end anges have axially aligned apertures I1, Il therethrough in alignment with hazard. 5 the axis of oscillation I3 providing journal sur- Objects of the invention are to provide an imfaces 5'6, '51 for receiving bearing pin 54, 55, as proved electric switch capable of long-life operashown especially in Figs. 2 and 3, to pivotally tion and relatively rapid frequency of making and mount the rocking member I 4 at each end thereof breaking electrical circuits through closed conand transversely of a divided protective housing tainers or cartridges having electrically conduo- 10 or casing I8 of cast or sheet metal construction. tive ilowable material therein; to provide for re- The rocking member including its seating porliability and safety of operation; to provide for tion I 4a is desirably mounted horizontally and rapidity of cyclical operation; to provide for difsubstantially parallel to and spaced upwardly ferent circuit connections of the switch; to profrom a flat base I 9a of the lower part I9 of the vide for oscillating the closed containers without 10 casing to facilitate limited rocking movement of movement in translation of the containers; to the structure I0. The end fianges I5, I 6 are provide for minimizing localized flexure of looped spaced from the lower sidewalls of the casing I8 flexible conductors carried by the assembly; and to facilitate also the limited rocking movement. to provide for simplicity, durability and compact- The rocking member I4 thus provides space ness of construction, convenience of manufacture 23 at 20 above the seating portion I 4a and interand servicing, and for effectiveness of operation. mediate the end anges I5, I 6 and extending These and other objects and advantages of the from side-to-side of the member I4 across the invention will be apparent from the following axis of oscillation I3 for receiving the closed condescription. tainers II, I2 therein.

In the accompanying drawings, which form a The rocking member I4 at its interconnecting part of this specification, web or seating portion I 4a disposed between the Fig'. 1 is a plan view of an electric safety switch flanges I5, I@ and desirably below the axis of constructed in accordance with and embodying oscillation I3, carries mounting means or plate the invention, parts being broken away, 2| of electrical insulating material such, for ex- Fig. 2 is a sectional view in elevation, taken 3l; ample, as hard rubber composition or a plastic along line 2-2 of Fig. 1, and or other suitable insulating material for support- Fig. 3 is a. perspective View of a rocking plating the containers such that the axis of oscillaform and cartridge assembly of the switch. tion intersects the containers. Preferably, the In the embodiment of the invention shown in mounting plate is secured and superimposed in the drawingsl the construction includesarocking face-to-face relation upon the seating portion -or oscillating structure I@ supporting detachably Ida. The construction makes feasible an insu- 4a plurality of two or more closed containers or lated mounting of the plurality or pair of closed cartridges II, I2 having electrically conductive containers II, I2 on the seat thus provided such owable material therein such, for example, as that they are disposed in spaced-apart insulated -mercury, such that the axis of oscillation of the if.; relation to the conductive seating portion Ida at structure, indicated by the numeral I3, intersects axially spaced-apart positions intermediate and each of the closed containers at an intermediate spaced from the end flanges I5, I6 and are disregion between the ends thereof and preferably, posed across the axis of oscillation I3 so as to be the axis of oscillation intersects the longitudinal intersected by said axis I3 at their intermediate axis of each container. By virtue oi the inter- 4:, regions and preferably at their longitudinal axes.

secting relationship quick tilting of the containers under oscillation about the axis I3 is effected without movement in translation of the containers Ias a whole, thus facilitating rapidity of making and breaking the electric circuits through the containers.

The rocking structure I has an elongated rocking member or platform Ii of stiff material such, for example, as steel or other strong metal plate material having spaced-apart, upturned Mounting means 22, 22 are provided at positions spaced-apart along the axes I3 for electrically engaging and detachably holding the containers, each means 22 being spaced from and disposed to a side of the axis of oscillation I3, as shown especially in Figs. 1 and 3, so as to embrace an electrically conductive end portion of the closed container. The means 22 includes a base 23 of thin, stiff, electrically conductive meta-l such, for example, as brass strip material having an upturned side margin 24 for contacting and registering against an end face of the container. A holding-contactor 25 of spring brass strip material having an upwardly bent, container-receiving end por-tion construction is superimposed on the base 23 for eiecting low-loss electrical contact with and detachably holding and clamping the container in place and for resisting accidental shifting of the container. At the same time, the holding-contactor 25, facilitates conveniently mounting and dismounting the container as for servicing the safety switch. The base strip 23 and the spring contactor 25 are maintained in good electrical contact one to the other and are secured to the rocking member as by one or more screw fasteners 26 of suitable conductive metal thrcadedly engaging the insulating material of the mounting plate 2l only.

Each pair of means 22, 22 for a container are aligned transversely of the rocking member so that the longitudinal axis of the container extends across the rocking member I4 substantially perpendicular to the direction of the axis of oscillation, and so that the axis of oscillation I3 intersects the container at an intermediate region or approximately its central region. This facilitates quick tilting of the container under oscillation of the rocking member about its axis without movement in translation of the container as a whole, which is advantageous for rapid frequency of making and breaking the electric circuit through the container.

For avoiding interference with an overlying upper part or detachable cover 2 of the housing I3 at the upper limit of rocking movement of the structure I3, the closed container I2 is desirably positioned nearest to and spaced inwardly a short distance from the end flange I6 of the rocking member Ill, while the other container II is spaced a substantial distance from the container I2 and also from the end flange I5, as shown especially in Figs. 1 and 3.

A T-shaped in section supporting element or terminal block 28 of suitable solid insulating material having spaced-apart apertures in the top or cross bar portion of the T projecting to the sides of the stem of the T, is mounted on and projects upwardly from the mounting plate 2| at the axis of oscillation I3 and between the spaced containers EI, I2, and a second supporting element or terminal block 23 of similar material and construction is mounted similarly with respect to the axis of oscillation but between the container II and the other end ange I5 of the rocking member Id. The terminal blocks 28, 23 having their top or cross bar portions uppermost and extending along the axis i3, are secured to the mounting plate 2l only as by suitable screw fasteners (not shown).

For connecting the container II to an electric circuit, insulated, electrically conductive wires 3G and 3l are connected to the respective screws 23, 23 of the one pair of means 22, 22 and to a pair of looped conductors 32, 33 of flexible, electrically conductive wire and electrically insulated construction, which wires 30, 3l may be continuations of the end portions of the conductors 32, 33. The

conductor 32 has an end portion extendingV through and secured in one aperture of the top portion of the terminal block 29, which conductor end portion is disposed at the axis of oscillation I3 so as to extend substantially vertical to the seating portion Illa of the rocking member I.- and to pass through the axis of oscillation I3 to promote minimum flexing of the conductor under oscillation of the rocking structure I3. A strain-relief member 36 of coiled, metal spring wire construction is positioned about the end portion of the conductor 32 and extends part way along the conductor, as shown especially in Figs. 1 and 3. The other flexible conductor 33 for the container II is similarly extended through and secured in the other aperture of the top portion of the terminal block 23, and has a suitabie strain-relief member 33.

The conductors 32, 33 have upwardly lcoper reaches in spaced-apart, substantially parallel relation to one another, each conductor extending in a single loop from the terminal block 23 at the axis of oscillation I3 and terminating in another end portion extending through and secured to an apertured terminal strip 35 of suitable solid insulating material. The terminal strip 35 extends transversely of the housing I8 at a position spaced substantially to one side of the axis of oscillation to eliminate sharp curvature of the looped reaches of the conductors, and is mounted at its ends upon upwardly extending projections 33, 3i of the base 19a, of the housing I3 as by suitable screw fasteners 38, 38.

The other end portions of the conductors 322',- 33 having suitable strain-relief members M, 33' extend through and are secured in spaced-apart apertures of the terminal strip 35, and are electrically connected by suitable insulated wires 33, 33 to spaced-apart bus bars 3l, 32 of suitable conductive metal, strip material on the upper surface of the terminal strip, the bus bars being held in place as by suitable screw fasteners 33, 3 which also engage and hold the wires 33, 33, as shown especially in Figs. 1 and 2.

The upwardly looped arrangement of the nexible conductors 32, 33 and their connection to the terminal block 29 at and along the axis of oscillation I3 advantageously accommodates the rocking or oscillating movement of the rocking structure I3 and at the same time, distributes the flexing stresses throughout the entire looped extent of the conductors. This facilitates long service life of the conductors despite relatively rapid frequency of oscillation of the rocking structure I9 and of making and breaking the electric circuit through the closed container I I.

A second pair of suitable flexible conductors 35, 33 for connecting electrically the closed container I2 to suitable spacer-apart bus bars il?, 33 on the terminal strip 35, and having suitable strainrelief members 34, 33 and 44, 45, are constructed and arranged like the flexible conductors 32, and extend likewise in the upwardly looped, spaced-apart, substantially parallel disposition from the apertured top portion of the terminal block 23 at the axis of oscillation I3 to the terminal strip 35.

The bus bars 4I, 42, 3l, 38 may be connected electrically to the remainder of the electric circuit of which the switch is to be a part by suitable wires (not shown) extending from the bus bars through a suitable aperture (not shown) in the adjacent end wall, for example, of the lower part I3 of the housing I8.

Each closed container may be of like construction; hence only the container II will be described in detail. The closed container I I is desirably of elongated cylindrical form having dimensions such that it can be mounted detachably on the mounting means 22, 22.

The container or cartridge II has closed end portions 43, 50 of suitable electrically conductive stii metal material, one of which portions 5U cilitating the alteration of the circuit-closing characteristics of the cartridge according to the particular disposition of the respective end p0rtions to the sides of the axis of oscillation. The

closed end portions 49, have their adjacentv open end portions maintained in spaced-apart, sealingly attached relation by a short cylindrical spacer 5I of hard rubber insulating material. A suitable quantity of electrically conductive flowable material such, for example, as mercury, is contained permanently in the cartridge II.

For further protecting the rocking structure Il! against electrical flash-over from the cartridge I2` to the metallic end ilange I6, a shield 52 of suitable thin, electrical insulatings sheet material may be secured to the end ange I6 throughout its entire extent. The other end flange I5 of the rocking member I4 is sufficiently remote from the other cartridge I I of the pair so that the ilange I5 does not require a shield of insulating sheet material.

The bearing pins 54, of stiff, wear-resistant steel or other metal for pivotally mounting the rocking structure il?, may be threadedly engaged with interiorly threaded hollow bosses of the sidewalls at the lower part I9 of the housing I3, and project inwardly from the sidewalls in axial alignment one to the other end in alignment with the axis of oscillation I3. The pins 54 and 55 extend into the journal bearings 56 and 51 of the end flanges I5, I B of the rocking member I4 so that the rocking structure I0 is supported horizontally at a sulicient height above the base ISa of the lower part I9 to permit the desired angular degree of oscillatory movement of the rocking structure IIJ.

A metal foot pedal 58 mounted at the exterior of the lower part I9, has connected to it a solid shaft 59 of steel o1' other strong metal material extending through hollow bearing bosses of the sidewalls at the other end of the lower part I9, as shown especially in Figs. l and 2. The foot pedal and shaft are preferably separable one from the other and removable from the housing, when desired as for servicing the switch.

An actuator Si! of steel or other suitable metal material is mounted adjustably on the shaft 59 at a position beyond `the end iiange I5 toward the sidewall of the housing I and has an extension 6I projecting radially of the shaft toward the axis of oscillation i3V for carrying at its free end a fixed pin 62 which may be of hardenedsteel, extending axially toward the end flange iii; The pin 52 is disposed in the space between tines 55, 54 of a forked portion of the end ange I5 to the side of the axis of oscillation I3 nearest the shaft 59. A vertically disposed, coiled metal spring 65 of the compression type between the base I9 of the housing and the extension BI of the actuator 5E! urges the rocking structure I0 to its normally tilted position shown in Fig. 2, and urges the foot pedal to its upper position 15 shown in broken lines in Fig. 2.

The actuator at a position diametrically opposite and axially spaced inwardly from the extension 6I is provided with a relatively short, second extension 56 disposed in the space between adjacent ends of spaced-apart limiting screws 61, 58 threadedly engaging vertically spaced-apart lugs B9, 'ID of the lower part I 9 of the case, as shown especially in Figs. 1 and 2. Lock nuts 1l, 12 on the limiting screws 61, BB'may be provided for maintaining the screws at a desired setting which establishes the desired limits 6 of the range of arcuate movement of thei extension 66 andthe desired number ordegrees of angular movement of the rocking structure for-rap'- idlyfmaking and breaking thecircuit through therespective cartridges I I, I2.v

The protective housing I 8 having lower and upper parts I9 and 21 maybe of rectangular shape, which parts may have corner bosses 13, 13 with interiorly threaded, aligned openings engageable by suitable hexagon-headed screw fasteners 14, 14 for holding thefupper and lower parts in tightly closedrelation to resist the entrance of inflammable liquids.

The safety switchr describedhereinabove may have the bus bars 4I, 42 and' 41, 48 connected electrically to one or more electrical circuits so that it functions as a two-pole normally open switch with the cartridges disposed as shown, or a `two-pole normally closedV switch having the cartridges in a reversed disposition relative to that shown, or a one-pole normally open and one-pole normally closed switch having only one of the cartridges in reversed disposition relative to that shown. For example, when the bus bar 42 is connected electrically directly to the bus bar 41, the switch will function as a one-pole doublethrow` switch having one cartridge reversed for a single circuit, three-wire hookup; With the bus bars and cartridges arranged as shown the switch functions as a double pole, single throw switch for a separate circuit, four-wire hookup. The switch thus makes feasible a plurality of diierent electrical circuit connections for meeting the requirements of different circuits and usage.

In the operation of the safety switch, assuming the same to be connected to the desired electrical circuit or circuits and the foot pedal 58 in the normal up position at 15 shown in broken lines in Fig. 2, andthe rocking structure I 0 in 'the normally tilted condition shown in-full lines in Fig. 2, with both mercury-containing cartridges I I, I2 in the normally open circuit condition, for example; the foot pedal 58 is pressed downwardly to the lower position at 16 shown in dot and dash lines in Fig. 2 to rotate the shaft andthe actuator 60 and thus compel oscillation of the'rocking structure and cartridges through a small degree of angular movement to the position at 11 shown in broken lines in Fig. 2, and against the resistance of the compression spring 85. The mercury in the conductive end portions 49, 49 of the respective cartridges flows across the hard rubber insulator 5 I into contact with the conductive end portions. 50, 50 of the cartridges thus completing the electrical circuits through both cartridges. Release of the downward' pressure on the foot pedal 58 permits the compression spring 65 to compel return movementor the rocking structure about the axis of oscillation to its normally tilted condition thus causing ow of the mercury in the opposite direction until the circuits throughk the cartridges are broken.

A smalldegree of angular movement of the rocking structure I3 about thevaxis of oscillation is all that' is requiredl to make and break quickly out departing as it is defined Vllclaim:

' 1. A switch for making and breaking electric circuits through a plurality of closed containers having electrically conductive iiowable material therein, said switch comprising a rocking platform having a seating portion of generally iiat form in the direction along and the direction across said platform disposed generally horizontal and terminating in upturned portions at the ends thereof and having a pivotal mounting at each upturned portion thereof for oscillation of said platform about a generally horizontal axis extending through the space overlying said seating portion between said upturned portions, mounting means carried by said platform at said space for detachably holding the closed containers in said space adjacent said seating portion with the containers in spaced-apart relation along said axis and in a side-by-side disposition across said axis and also for detachably holding the closed containers in said side-by-side disposition with said axis intersecting an intermediate region of each container s that by virtue of such intersection quick simultaneous tilting of all said containers under oscillation of said platform about said axis is effected without movement in translation of the containers as a whole, and flexible conductors carried by said platform for connecting the closed containers to the electric circuits, said flexible conductors being mounted on said platform at said axis and extending upwardly relative to said seating portion each in a single loop for mounting at a position spaced from a side of said platform for accommodating the oscillating movement of said platform about said axis.

2. A switch for making and breaking electric circuits through a plurality of closed containers having electrically conductive iiowable material therein, said switch comprising a rocking platform having a seatingportion of'generally flat form in the direction along and the direction across said platform disposed generally horizontal and terminating in upturned anges and having a pivotal mounting at each flange thereof for oscillation of said platform about a generally horizontal axis extending through the space overlying said seating portion between said anges, a supporting element of T-shape in cross-section on said seating portion at the region of said axis having the stern of the T projecting upwardly relative to said seating portion through said space and terminating in apertured cross-bar portions or" the T each extending away from a side of said stem in the direction along said axis and spaced substantially from said seating portion` flexible conductors for connecting the closed containers to the electric circuits, said conductors extending through and being secured in the apertures of said cross-bar portions and projecting upwardly therefrom at said axis each in a single loop for mounting at a position spaced from a side of said platform to accommodate the oscillating movement of said platform about said axis, and mounting means carried by said platform and disposed in said space for detachably mounting the closed containers in said space in spaced-apart relation along said axis and in side-by-side disposition across said axis with said axis intersecting an intermediate region of each container so that by virtue of such intersection quick simultaneous tilting of all said containers under oscillation of said platform about said axis is effected without movement in translation of the containers as a whole.

3. A switch for making and breaking electric 8 circuits through a plurality of closed containers having electrically conductive flowable material therein, said switch comprising a rocking platform for carrying the closed containers and having a seating portion of generally iiat form in the direction along and the direction across said platform disposed generally horizontal and terminating in upturned iianges and having a pivotal mounting at each flange thereof for oscillation of said platform about a generally horizontal axis extending through the space overlying said seating portion between said flanges, a supporting element of T-shape in cross-section on said seating portion at the region of said axis with the stem of the T projecting upwardly relative to said seating portion through said space and terminating in cross-bar portions of the T each extending away from a side of said stem in the direction along said axis and spaced substantially from said seating portion and each cross-bar portion having at least an aperture therethrough aligned with said axis, and iiexible conductors extending through and secured in the apertures of said cross-bar portions for electrically engaging the f closed containers to connect the saine to the electric circuits, said iiexible conductors extending upwardly in spaced-apart side-by-side relation from said cross-bar portions at said axis each in a single loop for mounting at a position spaced from aside of said platform to accommodate the oscillating movement of said platform about said axis.

Ll. A switch for making and breaking electric circuits through a pair of cartridges having electrically conductive iiowable material therein, said switch comprising an oscillating structure for supporting and imparting oscillating movement simultaneously to said pair of cartridges, said structure comprising a rocking platform of stiif plate material having a seating portion of generally flat form in the direction along and the direction across said platform disposed generally horizontal and terminating in upturned iianges to provide an overlying space between said fianges for receiving the pair of cartridges in side-by-side disposition across a generally horizontal axis of oscillation of the platform and in spaced-apart relation along said axis, means at said flanges for pivotally mounting said structure for oscillation thereof about said axis, a mounting plate of insulating material on a face of said seating portion to provide therewith a seat below said axis for supportingsaid cartridges in said disposition with said axis intersecting an intermediate region of each cartridge so that by virtue of such intersection quick simultaneous tilting of both cartridges under oscillation of said structure about said axis is eected without movement in translation of the cartridges as a whole, means on said mounting plate at positions spaced-apart along said axis for electrically engaging and detachably holding the pair of cartridges on said seat of the structure in said disposition and said spaced-apart relation, and means including iiexible conductors electrically `connected to the holding means and disposed on said mounting plate at positions spaced-apart along and aligned with said axis for connecting the cartridges to the electric circuits while accommodating the oscillating movement of said structure.

5. A safety switch for the rapid and frequent making and breaking of electric circuits, said switch comprising a housing having a base, a rocking structure in said housing having a seating portion of generally iiat form in the direction along and the direction across said rocking structure disposed generally horizontal and terminating in upwardly extending end portions to provide an overlying space between said end portions, means at said end portions for supporting said rocking structure pivotally relative to said housing for oscillation of said rocking structure about a generally horizontal axis extending through said space, a mounting plate of insulating material and generally flat form on said seating portion in said space, a pair of cartridges having electrically conductive flowable material therein mounted on said mounting plate in fixed relation thereto at positions spaced-apart along said axis and extending side-by-side across said axis in said space with said axis intersecting each cartridge in an intermediate region thereof so that by virtue of such intersection quick simultaneous tilting of both cartridges about said axis is effected without movement in translation of the cartridges as a whole, pairs Aof spaced-apart contactor elements of conductive resilient metal material on said mounting plate at said positions of said cartridges for electrically engaging and detachably mounting said cartridges on said seating portion, a terminal block of insulating material having a T-shape in section disposed to a side of each cartridge in alignment with said axis with the stem of the T projecting upwardly from said mounting plate and terminating in cross-bar portions of the T extending from the sides of said stem along said axis, and spaced-apart ilexible conductors disposed in pairs and supported by said base of said housing with each pair of conductors extending therefrom to one of the terminal blocks and being electrically connected to a pair of said contactor elements for a cartridge, each flexible conductor extending in a single upstanding loop to one of said Vcross-bar portions of a terminal block and intersecting the same at said axis for minimizing ilexure of the looped conductors under said oscillation of said rocking structure.

6. A switch for making and breaking electric circuits through a plurality of closed containers having electrically conductive owable material therein, said switch comprising a rocking platform having a base portion of generally ilat form in the direction along and the direction across said platform disposed generally horizontal and terminating in outwardly-turned portions at the ends 4of the platform and said platform having a pivotal mounting at each of the outwardly-turned end portions for oscillation of said platform about a generally horizontal axis extending through the space overlying said base portion between said outwardly-turned end portions, mounting means secured to vsaid base portion and disposed in said space for mounting the closed containers in said space adjacent said base portion with the containers in spaced-apart relation along said axis and in a side-by-side disposition across said axis and also for detachably holding the containers in said spaced-apart relation and in said side-byside disposition with said axis intersecting an intermediate region of each container so that by virtue of such intersection quick simultaneous tilting of all the containers under oscillation of said platform is effected without movement in translation of the containers as a whole, and flexible conductors associated with said mounting means for electrical connection with the containers to connect the same to electric circuits and said flexible conductors being mounted on said base portion at said axis and extending outwardly relative to said base portion and to said mounting means each in a single loop for mounting at a position spaced from a side of said platform to accommodate oscillating movement of said platform about said axis.

'7. A switch for making and breaking electric circuits through a plurality of closed containers having electrically conductive ilowable material therein, said switch comprising a rocking platform having a base portion of generally at form in the direction along and the direction across said platform disposed generally horizontal and terminating in upturned portions at the ends of the platform and said platform having a pivotal mounting at each upturned portion for oscillation of said platform about a generally horizontal axis extending through the space overlying said base portion between said upturned portions, mounting means including a conductor-supporting element secured to said platform and disposed in said space for mounting the closed containers in said space adjacent said base portion with the containers in spaced-apart relation along said axis and in side-by-side disposition across said axis and also for detachably holding the containers in said spaced-apart relation and in said side-by-side disposition with said axis intersecting an intermediate region of each container so that by virtue of such intersection quick simultaneous tilting of all the containers under oscillation of said platform is effected without movement in translation of the containers as a whole, and flexible conductors associated with said mounting means for electrical connection with the `containers to connect the same to electric circuits and said flexible conductors being mounted on said conductor-supporting element at said axis and extending upwardly relative to said base portion and to said conductor-supporting element each in a single loop for mounting at a. position spaced from a side of said platform to accommodate oscillating movement of said platform about said axis.

ANTON G. SEIFRIED.

Vickery Feb. 5, 1929 Seifried Dec. 23, 1947 Number 

